fix(docs): Update id.adoc (#892)

* fix(docs): Update id.adoc

- Remove `uuid.hex` generator
- Add `uuid2` generator
- Fix some links
- Remove `source` from groovy code blocks that are not complete classes

* fix(docs): Update id.adoc

Link to correct version of the hibernate reference

Author: matrei

build.gradle

@@ -120,7 +120,6 @@ asciidoctor {
                'docinfo1'      : '',
                'toc'           : 'left',
                'version'       : project.version,
-               'gormVersion'   : project.gormVersion,
                'sourcedir'     : "$checkOutDir/grails-src"
 }
 
@@ -163,6 +162,7 @@ task publishGuide(type: grails.doc.gradle.PublishGuide, dependsOn: ['apiDocs', '
         'gormApiDocs': "https://gorm.grails.org/${gormVersion}/api/",
         'springbootapi' :"https://docs.spring.io/spring-boot/docs/${springBootVersion}/api",
         'springBootReference' :"https://docs.spring.io/spring-boot/docs/${springBootVersion}/reference",
+        'hibernateReference': 'https://docs.jboss.org/hibernate/orm/5.6/userguide/html_single/Hibernate_User_Guide.html',
         'springBootVersion': project.springBootVersion,
         'springVersion': project.springVersion,
         'gradleVersion': project.gradleVersion

src/en/ref/Database Mapping/id.adoc

@@ -1,8 +1,6 @@
-
 == id
 
 
-
 === Purpose
 
 
@@ -31,7 +29,7 @@ Usage: `id(map)`
 
 Arguments:
 
-* `generator` (optional) - The name of the generator to use. Can be `increment`, `identity`, `sequence`, `seqhilo`, `uuid`, `uuid.hex`,  `assigned`, `select`, `foreign`, `sequence-identity`, `enhanced-sequence` or `enhanced-table`. See http://docs.jboss.org/hibernate/orm/current/userguide/html_single/Hibernate_User_Guide.html#identifiers-generators[Hibernate reference documentation] for more information.
+* `generator` (optional) - The name of the generator to use. Can be `increment`, `identity`, `sequence`, `seqhilo`, `uuid`, `uuid2`, `assigned`, `select`, `foreign`, `sequence-identity`, `enhanced-sequence` or `enhanced-table`. See {hibernateReference}#identifiers-generators[Hibernate reference documentation] for more information.
 
 WARNING: `hilo` generator was removed in Hibernate 5. See https://github.com/hibernate/hibernate-orm/blob/5.0/migration-guide.adoc[Hibernate 5 Migration Guide].
 
@@ -40,9 +38,9 @@ WARNING: `hilo` generator was removed in Hibernate 5. See https://github.com/hib
 * `params` (optional) - Any parameters to pass to the defined identity generator
 * `column` (optional) - The column name to map the identifier to. The remaining link:column.html[column] definition properties are also available.
 
-By default GORM uses the native strategy to generate a database identifier for each entity (typically an auto-incrementing column or a sequence). You can alter this with the `id` method's `generator` argument:
+By default, GORM uses the native strategy to generate a database identifier for each entity (typically an auto-incrementing column or a sequence). You can alter this with the `id` method's `generator` argument:
 
-[source,groovy]
+[,groovy]
 ----
 static mapping = {
     id generator: 'uuid'
@@ -51,7 +49,7 @@ static mapping = {
 
 You can also use the method to define a composite identifier:
 
-[source,groovy]
+[,groovy]
 ----
 static mapping = {
     id composite: ['title', 'author']
@@ -60,7 +58,7 @@ static mapping = {
 
 or change the name of the property that defines the identifier:
 
-[source,groovy]
+[,groovy]
 ----
 static mapping = {
     id name: 'title'
@@ -69,11 +67,11 @@ static mapping = {
 
 You can also alter the column definition:
 
-[source,groovy]
+[,groovy]
 ----
 static mapping = {
     id column: 'book_id', type: 'integer'
 }
 ----
 
-See the section on http://gorm.grails.org/6.0.x/hibernate/manual/index.html#identity[Custom Database Identity] in the user guide for more information.
+See the section on https://gorm.grails.org/{gormVersion}/hibernate/manual/index.html#identity[Custom Database Identity] in the user guide for more information.